CO2 Electrolysis Technologies: Bridging the Gap toward Scale-up and Commercialization

CO2 electroreduction (CO2E) converts CO2 into carbon-based fuels and chemical feedstocks that can be integrated into existing chemical processes. After decades of research, CO2E is approaching commercialization with several startups, pilot plants, and large initiatives targeting different products. Here, we analyze the global efforts in scaling up CO2E, addressing implementation challenges and proposing methods for acceleration. We present a comparative analysis of key performance indicators (KPIs) between laboratory and industrial settings and suggest a stepwise technoeconomic analysis (TEA) framework, supported by industrial data, exploiting interactions within the academic and industrial communities. We identify the lack of systems-oriented standardization and durability as the main bottlenecks slowing down progress in the lab-to-prototype-to-market pathway of CO2E technologies. Inspired by electrolysis and fuel cell technologies, we outline protocols to advance fundamental research and aid catalyst development progress in performance, upscaling, and technology readiness level of CO2E.


S2. Global CO2 evasion potential
We conducted an estimation of the global CO2 evasion potential by fully replacing fossil fuels with CO2E in the production of key chemicals within the petrochemical and fuel industries. he The CO2 emissions avoided from current industrial production is obtain by simply multiplying the current production volume by its Carbon footprint (Table S1).The obtained value is equal to the total CO2 emissions associated with its actual production.
The data calculated was summarized in the Table 1 of the main text.

S1.2 CO2 for CO2E feedstock
The CO2 needed as a feedstock is obtained by multiplying the total annual production volume (Table S1) by the stoichiometric relationship from the corresponding electrochemical reduction reactions.An example calculation for ethylene is detailed below: For jet fuel production, CO2E serves as the source of CO, which is then subject to various technologies to undergo further upgrading.Consequently, the CO2 utilized as feedstock for jet fuel is identical to the CO derived from CO2E.The data has been sourced from a combination of industry reports, white papers, and publicly available company documents, along with academic publications where available.This blend of sources provides a comprehensive view, though it's important to note the varying levels of peer review and formal validation among these documents.

S3. Technology Readiness Level (TRL)
Table S5 | Technology Readiness Level (TRL), incorporating the commonly used TRL grading standards from National Aeronautics and Space Administration (NASA) and the US Department of Defense (DoD), and also the TRLs for electrolyzers from the International Energy Agency. 40,41

TRL Explanation
TRL-1 Basic principles: Technology concept has been formulated, but it is yet to be experimentally verified.

TRL-2
Technology concept validation: Feasibility of the technology has been shown through laboratory studies.
TRL-3 Proof of concept: Initial experimentation confirms the technology's viability in a laboratory environment.

TRL-4
Component and subsystem validation: The technology has been tested in a laboratory setting, demonstrating its functionality in simulated conditions.

TRL-5
Validation in relevant environment: The technology has been tested in a relevant environment, displaying its basic performance.

TRL-6
System model or prototype demonstration: The technology has been showcased in a relevant operational environment, exhibiting complete performance.

TRL-7
System prototype demonstration: The technology has been proven to be effective and practical through testing in an operational system.

TRL-8
System complete and qualified: The technology has been proven to be reliable, stable, and effective under operational conditions.

TRL-9
Actual system proven in operational environment: The technology has been successfully demonstrated in actual applications and is ready for commercial use.

TRL-11
Huge market success and classic technology.
chemicals targeted for replacement were ethylene (C2H4), ethanol (C2H5OH), methanol (CH3OH), carbon monoxide (CO), formic acid (HCOOH) and Jet fuel.This estimation represents an upper bound, considering two significant factors.The first factor considers the global CO2 emissions that would be avoided by discontinuing the current industrial output reliant on fossil fuels.The second factor accounts for the CO2 consumed as a feedstock in the process of utilizing CO2E.Together, these factors contribute to the maximum potential of CO2 evasion resulting from the complete replacement of fossil fuels with CO2E in the production of key chemicals within the petrochemical and fuel industries.It does not consider the carbon footprint associated with CO2E and upstream (e.g., Direct air capture or flue gas carbon capture) nor downstream technologies.It neither considers the emissions originated from combustion of such chemicals after their production S1.1 CO2 from current industrial production reliant on fossil fuels

Table S1 |
Uses and synthesis methods of common chemicals

Table S2 |
End-products' market overview and carbon emissions.